Attempts have heretofore been made to introduce color into liquid crystal displays. For example, an absorbing filter has been placed between the light source and the cell or the observer and the cell. The difficulty with such devices is that they have the same color when they are turned on as when they are turned off. Special liquid crystal materials have also been utilized in which color has been introduced into the dye in the molecule of the nematic liquid crystal material. These have the disadvantage that they require polarizing filters in addition to the liquid crystal cell, and are capable of producing only a single color in one cell.
There is, therefore, a need for a new and improved display device which is capable of producing more than one color in a single cell, and which changes color when activated and changes to another color when inactivated.